For the production of usable protein for humans and animals, experimenters are showing much interest in microorganisms which produce single cell proteins. Possible suggested foods for the microorganisms have included hydrocarbons such as petroleum and fractions thereof, e.g., natural gas, naphtha, kerosene, and fuel oil, and other carbon-containing materials such as oxygenated hydrocarbons, carbohydrates, and cellulosic substances. It is desirable to be able to feed crude, instead of refined, materials to the microorganisms in order to avoid refining costs.
Crude methanol in particular is a possible food source for certain microorganisms, as has been suggested in the literature. How to increase yeast cell growth where crude methanol or crude ethanol is the carbon source is the specific problem addressed by the present invention.
Although the prior art has suggested various possible lists of carbon sources for various lists of microorganisms, many microorganisms are very selective as to the foods which they can utilize.
The present invention has solved a problem which hitherto had not even been recognized in the prior art: i.e., 2-methyl-1-propanol is detrimental to the growth of certain yeasts which feed on crude methanol or crude ethanol.
It is an object of the present invention to increase the yield of certain yeasts on the carbon sources crude methanol and crude ethanol.